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Author: Subject: Cyanate to cyanide - fresh thread
Friedrich Wöhler
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[*] posted on 13-2-2004 at 06:41


Hallo Swedish friend,

Its nice to know, you must not search on your keybord for the "ö" in my nick... :D

Hi Polverone,

I don't know, if bulding ammonium cyanide from coal and ammonia is discussed already anywhere in forum.
Want we to think about together? I have a detailed picture in my head, how to do this practically. But: I still found no information about the needed temperature running this reaction. :(
I just opened a new thread (my first own opening) about reactions from dry ammonia. It where a good place, if that is still undiscussed.

By the way...what are the English trivial names of solutions of ammonia and of alcali hydroxides and CaOH-suspension?




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Polverone
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[*] posted on 13-2-2004 at 17:06


No, the production of ammonium cyanide has not been discussed here. I recall from <A HREF="http://bcis.pacificu.edu/~polverone/muspratt.html">Muspratt </A> (or perhaps the <A HREF="http://www.1911encyclopedia.org">1911 Encyclopedia</A>;) that a mixture of natural gas and ammonia yields some ammonium cyanide when burned.

Trivial names:

An aqueous solution of ammonia is often called ammonia water, ammonium hydroxide (somewhat of a misnomer), or simply ammonia. NaOH is called lye or caustic soda (this second name is antiquated). KOH may be called caustic potash (this is also an antiquated name). Ca(OH)2 is called slaked lime.




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S.C. Wack
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[*] posted on 9-3-2005 at 23:21


I recall reading somewhere that ammonium cyanide sublimes by heating a mixture of ferrocyanide and ammonium chloride. No details on yield though. Anyways, I ran into this cyanate to cyanide experiment on Gallica so I thought I'd throw it up FWIW. It is, of course, in French.

I think that the yield is good considering the reaction is more like: 5 KOCN -> 3 KCN + K2CO3 + CO2 + N2. Thus the use of waste CO over the hot cyanate in patents.

[Edited on 10-3-2005 by S.C. Wack]

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prole
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[*] posted on 10-2-2006 at 11:48
shelf life of potassium cyanide and CO2


According to the Merck Index, KCN decomposes gradually by contact with CO2 and moisture. Is there a substance that one could wrap in a tea bag and insert into the KCN-containing bottle that will absorb CO2 and not react with the KCN?

Does anyone know the shelf-life of KCN in a sealed amber jar?

I may soon prepare a small quantity from HCN and KOH, and I don't want to lose any to CO2 or moisture after the gas-generating ordeal, unless the losses are negligible, because I don't ever plan to prepare more. I've seen a lot of commercial CO2 absorbents on google, but I'm wondering if there's something more OTC that could be used. Thanks for any responses.

-prole




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hinz
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[*] posted on 10-2-2006 at 12:49


Prole I think that the KCN will not decompose if it comes in contact with water and CO2.
The CO2 and the water react with each other forming carbonic acid.

CO2 + H2O <==> H2CO3

Since HCN is a very weak acid, carbonic acid, which isn't also a strong acid, will liberate the HCN from KCN or oher cyanide salts. But if your storage container is closed the HCN can't get out of it and the whole reaction stays in its equilibrium.

H2CO3 + KCN <==> HCN + KHCO3

So, there is no need of a CO2 absorbent in a storage container, if there is no excange with the air. I think the shelf-life of KCN in a sealed jar is nearly unlimited. (if it's really well sealed)

[Edited on 10-2-2006 by hinz]
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6dthjd1
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[*] posted on 22-2-2019 at 13:22


Has anyone tried the method of combining Cyanuric acid, potassium carbonate , and charcoal in an effort to make potassium cyanate which is then reduced to cyanide?

Essentially this is analogous to Polverone's method involving the sodium salts.

I have done this process and upon testing a chunk of my suspected potassium cyanide with a cyanide test kit strip no detectable cyanide was found.

This is interesting as I found limited evidence that the substance seemed to be deliquescent. Potassium cyanate is not deliquescent.
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walruslover69
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[*] posted on 23-2-2019 at 10:26


Quote: Originally posted by 6dthjd1  
Has anyone tried the method of combining Cyanuric acid, potassium carbonate , and charcoal in an effort to make potassium cyanate which is then reduced to cyanide?

Essentially this is analogous to Polverone's method involving the sodium salts.

I have done this process and upon testing a chunk of my suspected potassium cyanide with a cyanide test kit strip no detectable cyanide was found.

This is interesting as I found limited evidence that the substance seemed to be deliquescent. Potassium cyanate is not deliquescent.


I have tried this with sodium carbonate and it did produce some cyanide. The separation was a pain and i have no idea about the purity, but when i dissolved some of the solid in water, and added it to a solution of HCl and dissolved iron, prussian blue precipitated indicating some amount of cyanide.
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[*] posted on 23-2-2019 at 15:40


How did you separate? Did you use methanol with vacuum removal of methanol or slow evaporation on cold, dry winter days or a more inert atmosphere?
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